1/*
  2 * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
  3 *
  4 * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
  5 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  6 * Parts Copyright : Ian Molton <spyro@f2s.com>
  7 *                   Andrew Zabolotny <zap@homelink.ru>
  8 *
  9 *  This program is free software; you can redistribute  it and/or modify it
 10 *  under  the terms of  the GNU General  Public License as published by the
 11 *  Free Software Foundation;  either version 2 of the  License, or (at your
 12 *  option) any later version.
 13 *
 14 * Notes:
 15 *     This is a wm97xx extended touch driver supporting interrupt driven
 16 *     and continuous operation on Marvell Zylonite development systems
 17 *     (which have a WM9713 on board).
 18 */
 19
 20#include <linux/module.h>
 21#include <linux/moduleparam.h>
 22#include <linux/kernel.h>
 23#include <linux/init.h>
 24#include <linux/delay.h>
 25#include <linux/gpio.h>
 26#include <linux/irq.h>
 27#include <linux/interrupt.h>
 28#include <linux/io.h>
 29#include <linux/wm97xx.h>
 30
 31#include <mach/hardware.h>
 32#include <mach/mfp.h>
 33#include <mach/regs-ac97.h>
 34
 35struct continuous {
 36	u16 id;    /* codec id */
 37	u8 code;   /* continuous code */
 38	u8 reads;  /* number of coord reads per read cycle */
 39	u32 speed; /* number of coords per second */
 40};
 41
 42#define WM_READS(sp) ((sp / HZ) + 1)
 43
 44static const struct continuous cinfo[] = {
 45	{ WM9713_ID2, 0, WM_READS(94),  94  },
 46	{ WM9713_ID2, 1, WM_READS(120), 120 },
 47	{ WM9713_ID2, 2, WM_READS(154), 154 },
 48	{ WM9713_ID2, 3, WM_READS(188), 188 },
 49};
 50
 51/* continuous speed index */
 52static int sp_idx;
 53
 54/*
 55 * Pen sampling frequency (Hz) in continuous mode.
 56 */
 57static int cont_rate = 200;
 58module_param(cont_rate, int, 0);
 59MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
 60
 61/*
 62 * Pressure readback.
 63 *
 64 * Set to 1 to read back pen down pressure
 65 */
 66static int pressure;
 67module_param(pressure, int, 0);
 68MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
 69
 70/*
 71 * AC97 touch data slot.
 72 *
 73 * Touch screen readback data ac97 slot
 74 */
 75static int ac97_touch_slot = 5;
 76module_param(ac97_touch_slot, int, 0);
 77MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
 78
 79
 80/* flush AC97 slot 5 FIFO machines */
 81static void wm97xx_acc_pen_up(struct wm97xx *wm)
 82{
 83	int i;
 84
 85	msleep(1);
 86
 87	for (i = 0; i < 16; i++)
 88		MODR;
 89}
 90
 91static int wm97xx_acc_pen_down(struct wm97xx *wm)
 92{
 93	u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
 94	int reads = 0;
 95	static u16 last, tries;
 96
 97	/* When the AC97 queue has been drained we need to allow time
 98	 * to buffer up samples otherwise we end up spinning polling
 99	 * for samples.  The controller can't have a suitably low
100	 * threshold set to use the notifications it gives.
101	 */
102	msleep(1);
103
104	if (tries > 5) {
105		tries = 0;
106		return RC_PENUP;
107	}
108
109	x = MODR;
110	if (x == last) {
111		tries++;
112		return RC_AGAIN;
113	}
114	last = x;
115	do {
116		if (reads)
117			x = MODR;
118		y = MODR;
119		if (pressure)
120			p = MODR;
121
122		dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
123			x, y, p);
124
125		/* are samples valid */
126		if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
127		    (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
128		    (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
129			goto up;
130
131		/* coordinate is good */
132		tries = 0;
133		input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
134		input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
135		input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
136		input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
137		input_sync(wm->input_dev);
138		reads++;
139	} while (reads < cinfo[sp_idx].reads);
140up:
141	return RC_PENDOWN | RC_AGAIN;
142}
143
144static int wm97xx_acc_startup(struct wm97xx *wm)
145{
146	int idx;
147
148	/* check we have a codec */
149	if (wm->ac97 == NULL)
150		return -ENODEV;
151
152	/* Go you big red fire engine */
153	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
154		if (wm->id != cinfo[idx].id)
155			continue;
156		sp_idx = idx;
157		if (cont_rate <= cinfo[idx].speed)
158			break;
159	}
160	wm->acc_rate = cinfo[sp_idx].code;
161	wm->acc_slot = ac97_touch_slot;
162	dev_info(wm->dev,
163		 "zylonite accelerated touchscreen driver, %d samples/sec\n",
164		 cinfo[sp_idx].speed);
165
166	return 0;
167}
168
169static void wm97xx_irq_enable(struct wm97xx *wm, int enable)
170{
171	if (enable)
172		enable_irq(wm->pen_irq);
173	else
174		disable_irq_nosync(wm->pen_irq);
175}
176
177static struct wm97xx_mach_ops zylonite_mach_ops = {
178	.acc_enabled	= 1,
179	.acc_pen_up	= wm97xx_acc_pen_up,
180	.acc_pen_down	= wm97xx_acc_pen_down,
181	.acc_startup	= wm97xx_acc_startup,
182	.irq_enable	= wm97xx_irq_enable,
183	.irq_gpio	= WM97XX_GPIO_2,
184};
185
186static int zylonite_wm97xx_probe(struct platform_device *pdev)
187{
188	struct wm97xx *wm = platform_get_drvdata(pdev);
189	int gpio_touch_irq;
190
191	if (cpu_is_pxa320())
192		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO15);
193	else
194		gpio_touch_irq = mfp_to_gpio(MFP_PIN_GPIO26);
195
196	wm->pen_irq = gpio_to_irq(gpio_touch_irq);
197	irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
198
199	wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
200			   WM97XX_GPIO_POL_HIGH,
201			   WM97XX_GPIO_STICKY,
202			   WM97XX_GPIO_WAKE);
203	wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
204			   WM97XX_GPIO_POL_HIGH,
205			   WM97XX_GPIO_NOTSTICKY,
206			   WM97XX_GPIO_NOWAKE);
207
208	return wm97xx_register_mach_ops(wm, &zylonite_mach_ops);
209}
210
211static int zylonite_wm97xx_remove(struct platform_device *pdev)
212{
213	struct wm97xx *wm = platform_get_drvdata(pdev);
214
215	wm97xx_unregister_mach_ops(wm);
216
217	return 0;
218}
219
220static struct platform_driver zylonite_wm97xx_driver = {
221	.probe	= zylonite_wm97xx_probe,
222	.remove	= zylonite_wm97xx_remove,
223	.driver	= {
224		.name	= "wm97xx-touch",
225	},
226};
227module_platform_driver(zylonite_wm97xx_driver);
228
229/* Module information */
230MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
231MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
232MODULE_LICENSE("GPL");